According to the invention, there is provided a steering apparatus for marine craft having a stern and a propulsion unit mounted on the stern. The system includes a first bracket which is connectable to the stern of the marine craft. There is a second bracket connectable to the propulsion unit. The second bracket is rotatably connected to the first bracket for relative rotation about an axis of rotation. The propulsion unit can be rotated about the axis of rotation relative to the stern of the craft. The second bracket has a cylindrical bore extending therethrough. A piston is reciprocatingly received within the bore, slidingly engages the bore and has a piston rod connected thereto. The piston rod is operatively connected to the propulsion unit. Preferably the piston rod is coaxial with the axis of rotation.
In one example, the second bracket has an actuator portion. The bore extends through the actuator portion. The second bracket comprises a cylinder for the actuator. The actuator portion may have a cylindrical bushing surface. The first bracket has an extension. The extension has a cylindrical bore rotatably receiving the bushing surface. The bushing surface and the cylindrical bore are co-axial with the axis of rotation.
The invention offers significant advantages over the prior art. It provides a hydraulic steering system for stern drives where there is no arcuate travel of the hydraulic actuator when the stern drive is tilted. At the same time, it significantly reduces the complexity of the mechanism compared to U.S. Pat. No. 6,276,977 because it does not require a separate outer or inner cylinder apart from a bore through the swivel bracket itself. In effect, a portion of the swivel bracket becomes the cylinder of the actuator.
Nor is it feasible to readily modify the above U.S. patent to delete the inner and outer cylinders. This is because the extensions to the clamp brackets are beside the cylindrical portion of the swivel bracket which therefore does not present a continuous cylindrical bore for a cylinder. Furthermore, the outer cylinder is required in order to act as a pin in the hinged connection between the extensions to the clamp brackets and the cylindrical portion of the swivel bracket.
Corrosion cannot occur between the hydraulic cylinder and the tilt bracket according to the invention because they comprise a single component in the preferred embodiment.